Something is rotten in the state of American political life. The U.S. (among other nations) is increasingly characterized by highly polarized, informationally insulated ideological communities occupying their own factual universes.
Within the conservative political blogosphere, global warming is either a hoax or so uncertain as to be unworthy of response. Within other geographic or online communities, vaccines, fluoridated water and genetically modified foods are known to be dangerous. Right-wing media outlets paint a detailed picture of how Donald Trump is the victim of a fabricated conspiracy.
None of that is correct, though. The reality of human-caused global warming is settled science. The alleged link between vaccines and autism has been debunked as conclusively as anything in the history of epidemiology. It’s easy to find authoritative refutations of Donald Trump’s self-exculpatory claims regarding Ukraine and many other issues.
Yet many well-educated people sincerely deny evidence-based conclusions on these matters.
In theory, resolving factual disputes should be relatively easy: Just present the evidence of a strong expert consensus. This approach succeeds most of the time when the issue is, say, the atomic weight of hydrogen.
But things don’t work that way when the scientific consensus presents a picture that threatens someone’s ideological worldview. In practice, it turns out that one’s political, religious, or ethnic identity quite effectively predicts one’s willingness to accept expertise on any given politicized issue.
Motivated reasoning is what social scientists call the process of deciding what evidence to accept based on the conclusion one prefers. As I explain in my book The Truth About Denial: Bias and Self-Deception in Science, Politics, and Religion, this very human tendency applies to all kinds of facts about the physical world, economic history and current events.
The interdisciplinary study of this phenomenon has exploded over just the past six or seven years. One thing has become clear: The failure of various groups to acknowledge the truth about, say, climate change, isn’t explained by a lack of information about the scientific consensus on the subject.
Instead, what strongly predicts denial of expertise on many controversial topics is simply one’s political persuasion.
A 2015 metastudy showed that ideological polarization over the reality of climate change actually increases with respondents’ knowledge of politics, science, and/or energy policy. The chances that a [ … ]